1. Field of the Invention
The invention relates to a built-in scanner, and more particularly, to a built-in scanner that scans transparent and reflective documents by using single light source.
2. Description of the Prior Art
Science progresses have significantly brought many scanners to be manufactured for achieving kinds of requirements. Except a requirement of higher resolution, the scanners are requested to be standard equipment for building in a computer case.
Conventionally, the built-in scanners are usually constrained by usable spaces, and therefore the scanning range is serious influenced because the sizes of the mechanical and optical components can not be effective reduced. Furthermore, lights illuminated from two ends of the lamps are usually with insufficient brightness for scanning. For example, in the FIG. 4, it is obvious that the illuminating effective length 402 will be shorter than the lamp length 401. The darkest brightness of the illuminating effective length 402 is a half of the lamp center (B.sub.0.5). A label 403 indicates a lamp length with at least 90% brightness of the lamp center (B.sub.0.9), and ineffective parts that indicated by a label 404 are about 20 millimeters. Clearly, only the length indicated by the label 403 can be applied as a light source for scanning. Therefore, the effective range is constrained under the area of 4 inches by 6 inches.
Typical built-in scanners can only scan reflective documents, such as papers, photo, and business cards because the light source is usually allocated at the scanned side of the scanned documents. Those transparent documents such as projection slides or lantern slides can not be scanned directly in the conventional built-in scanners, and additional peripheral devices are needed for scanning such documents. A requirement has been arisen to disclose a built-in scanner, in which both the reflective and the transparent documents can be scanned without additional peripheral devices.